Period tracker guide — how to track your cycle and predict your next period

📅 April 2026⏱ 5 min read🏷 Women's Health

This article is for informational purposes only and is not medical advice. Consult a healthcare provider for health concerns.

Tracking your menstrual cycle is one of the most useful health habits you can build. It predicts your next period, reveals your fertile window, and — over time — helps you spot irregularities that might need medical attention. Here's how to do it properly.

What to track and why

At minimum, track the first day of your period (day 1 of the cycle) and the last day. Over 3–6 months this reveals:

Your average cycle length (first day of one period to first day of the next)
Your average period length (how many days bleeding lasts)
Whether your cycle is regular or variable

What's a normal cycle length?

The average is 28 days but "normal" spans 21–35 days. A cycle that's consistently 26 days is just as normal as a 30-day cycle. What matters is consistency — if your cycle length varies by more than 7 days month to month, that's worth noting and potentially discussing with a doctor.

💡 Cycle vs period — the common confusion

Your cycle length is the number of days from the first day of one period to the first day of the next. Your period length is just the days of bleeding. A 28-day cycle with a 5-day period means you bleed days 1–5 and have 23 days without bleeding before it restarts.

The four phases of the menstrual cycle

Menstrual phase (days 1–5 avg): Uterine lining sheds. Estrogen and progesterone are at their lowest.
Follicular phase (days 1–13 avg): Overlaps with menstruation. Estrogen rises as a follicle develops. Energy and mood often improve.
Ovulatory phase (around day 14): LH surge triggers egg release. Fertile window peaks here.
Luteal phase (days 15–28 avg): Progesterone rises. If no pregnancy, it drops and the cycle restarts. PMS symptoms typically occur in the late luteal phase.

📅 Free Period Calculator

Enter your last period date and cycle length. See your next 6 periods, fertile window and ovulation date.

Track My Cycle →

When to see a doctor

Tracking makes it easy to spot when something's off. Consult a healthcare provider if:

Your period is consistently absent for 3+ months (outside of pregnancy)
Cycle length varies by more than 7–9 days each month
Bleeding is extremely heavy (soaking through a pad/tampon every hour for several hours)
You experience severe pain that disrupts daily activity
Spotting occurs consistently between periods